SEM of the ciliary processes after paracentesis.

Corneal perforation and withdrawal of aqueous humor (paracentesis) represents a practical means for producing controlled trauma to the eye. The sequence of events triggered by paracentesis has been carefully studied by in vivo and in vitro microscopy and other means. These observations have proven especially helpful in elucidating the physiology and pharmacology of ocular trauma. Scanning electron microscopy of the ciliary processes of the rabbit has proven a sensitive indicator of the response to prostaglandin, a mediator of the paracentesis reaction. We used SEM to invetigate changes in the ciliary processes induced by paracentesis. We also examined the opposite eye for a consensual response. The effect of prior treatment with aspirin or nerve block was assessed in both the traumatized eye and the fellow eye. In an untreated animal, a consensual response to trauma was present and demonstrable by scanning electron microscopy. The direct response was more effectively blocked by aspirin than by local anesthesia. Both pretreatments were effective in reducing the consensual reaction.